The invention relates to a handle for a wrench for rotating a member (e.g., a nut) in a torquing plane substantially perpendicular to the axis of rotation of the member. The invention, in particular, relates to such a wrench having an ergonomically designed handle to reduce stress and increase productivity during use.
A typical prior art crescent wrench is shown in FIG. 5. The wrench includes a head portion 100 for engaging a member, such as a nut or the head of a bolt, and a handle portion 200 for applying torquing force to the member in a direction which is substantially coplanar with a torquing plane lying in the major plane of the wrench body. Since the handle portion 200 is substantially planar, it presents a problem in that the greatest amount of stress is concentrated at the thinnest part of the handle. That is, a user""s hand presses against the thinnest part of the handle when the wrench is pushed or pulled in the torquing plane. Extended use of the wrench can cause significant discomfort and potential injuries from repetitive manipulation. This discomfort can cause improper and inefficient use of the tool.
A wrench having a cylindrical handle portion is also known. However, the cylindrical handle also places a high stress concentration on the hand, causing serious discomfort and preventing proper performance of the torquing movement facilitated by using the tool. Such improper use may cause further injury and increase the time required to complete a project for which the tool is intended.
Other tools, such as hammers, include handles which are generally elliptical in cross-section. In these cases, the major axis of the ellipse is arranged such that it is coplanar with the direction of the applied force. This orientation of the elliptically shaped handle is intended to provide more comfort than a planar or circular handle when held in the palm and gripped by the fingers. While this design may present a more appealing tactile feel when the tool is first gripped, if employed in a wrench handle it would concentrate the stress on the part of the handle having the least surface area, since the major axis of the elliptical handle is coplanar with the direction of the applied force. Accordingly, this orientation of an elliptical handle, if used in a wrench which is pushed or pulled in a torquing plane, would accentuate the problem discussed above, since the thinnest part of the ellipse receives the applied force. Accordingly, the problem of discomfort, injury, improper use, and decreased efficiency would not be solved by incorporating a handle of this type.
It would be desirable to provide a wrench having an ergonomic handle that is comfortable to hold, and functions to reduce physical stress and injury during use, while at the same time facilitating proper use and increased efficiency. No attempts have been made to address these problems in the area of wrenches as defined above.
It is an object of the present invention to overcome the drawbacks of the prior art, particularly to provide a wrench for rotating a member in a torquing plane substantially perpendicular to the axis of rotation of the member having an ergonomic handle which facilitates proper and efficient use of the wrench by reducing the stress placed on the hand and arm.
In accordance with one object of the present invention, a wrench for rotating a member in a torquing plane substantially perpendicular to the axis of rotation of the member is provided, including a head portion for engaging a member, such as a bolt, and a handle extending from the head portion in a first longitudinal direction. The handle is substantially elliptical, having a major axis a and a minor axis b when viewed in a cross-sectional plane perpendicular to the first longitudinal direction, and the major axis a is arranged substantially perpendicular to the torquing plane.
In accordance with another embodiment of the present invention, a wrench for rotating a member in a torquing plane substantially perpendicular to the axis of rotation of the member is provided, having a head portion for engaging a member, a handle extending therefrom in a first longitudinal direction, and an elongate main body portion extending from the head portion and passing through the handle portion in the first longitudinal direction. The main body portion, when viewed in the cross-sectional plane perpendicular to the first longitudinal direction, is substantially planar and extends in a second direction that is substantially coplanar with said torquing plane.
In accordance with a third embodiment of the present invention, a wrench for rotating a member in a torquing plane substantially perpendicular to the axis of rotation of the member is provided, having a head portion for engaging a member, and a main body portion formed integrally with the head portion.
In accordance with a preferred embodiment of the present invention, a wrench for rotating a member in a torquing plane substantially perpendicular to the axis of rotation of the member is provided, having a head portion for engaging a member and an elongate main body portion extending therefrom in a first longitudinal direction. The wrench further includes a handle formed separately from the head portion and the main body portion, and the handle is assembled over the main body portion.
In accordance with another embodiment of the present invention, a wrench for rotating a member in a torquing plane substantially perpendicular to the axis of rotation of the member is provided, having a head portion for engaging a member and a handle extending therefrom in a first longitudinal direction. The handle being substantially elliptical in shape, essentially fulfills the equation x2/a2+y2/b2=1, where a greater than b, and the ratio of a:b ranges from 1.10:1 to 1.25:1.
In accordance with another embodiment of the invention, a wrench for rotating a member in a torquing plane substantially perpendicular to the axis of rotation of the member is provided, having a head portion for engaging a member and a handle extending therefrom in a first longitudinal direction. The handle includes an inner core extending along the first longitudinal direction and having an inner surface which opposing the main body portion of the wrench, and an external layer extending along the first longitudinal direction and substantially covering an outer surface of the inner core.
In accordance with yet another embodiment of the invention, a wrench for rotating a member in a torquing plane substantially perpendicular to the axis of rotation of the member is provided, having a head portion for engaging a member and a handle extending therefrom in a first longitudinal direction. The handle includes an inner core extending along the first longitudinal direction and having an inner surface which opposing the main body portion of the wrench, and the inner core comprises a hard grade elastomer material.
In accordance with another embodiment, a wrench for rotating a member in a torquing plane substantially perpendicular to the axis of rotation of the member is provided, having a head portion for engaging a member and a handle extending therefrom in a first longitudinal direction. The handle includes an inner core extending along the first longitudinal direction and having an inner surface which opposing the main body portion of the wrench, and the inner core comprises a hard grade elastomer material, such as a polypropylene material.
In accordance with still another embodiment, a wrench for rotating a member in a torquing plane substantially perpendicular to the axis of rotation of the member is provided, having a head portion for engaging a member and a handle extending therefrom in a first longitudinal direction. The handle includes an inner core extending along the first longitudinal direction and an external layer extending along the first longitudinal direction and substantially covering an outer surface of the inner core, and the external layer comprises a flexible grade elastomeric material.